Thrinchostoma (T.) yunnanense Niu & Zhu

Zeqing Niu, Feng Yuan, Pia Oremek, Feng Liu & Chaodong Zhu, 2016, Thrinchostoma Saussure, little known bee genus from China, with description of a new species (Hymenoptera: Halictidae), Zoological Systematics 41 (2), pp. 207-215 : 212-214

Thrinchostoma (T.) yunnanense Niu & Zhu , sp. nov.

( Figs 17–32 )

Diagnosis. The new species is similar to T. assamense Sladen, 1915 . The female can be distinguished from T. assamense by disc of T1 with very sparse and fine punctures, T2 without broad orange apical margin ( Fig. 31 ); the male has two transverse rows of spines at basal margin of S5, and number 7 at left side and 6 at right side ( Fig. 21 ).

Description. Male. BL=10.0 mm ( Fig. 17 ). Head obviously longer than broad, HL: HW=64: 49 ( Fig. 18 ); antenna filiform, flagellum 11-segmented, first flagellomere nearly as long as broad, second to tenth flagellomeres about equal in length, each segment about 1.5 times as long as broad, last flagellomere nearly 2.5 times as long as broad, last flagellomere not bent; malar area near twice as long as the width of mandible base (12:6), and nearly one-third as long as eye length (12:35) ( Fig. 19 ); gena narrower than eye, GW: EW=5: 20 ( Fig. 19 ); forewing with a conspicuous dark spot of dense hairs near median part of second submarginal crossvein, and the second submarginal crossvein not reaching the radical nervure ( Fig. 23 ); T1 and T2 polished, respectively with a transverse band ( Fig. 20 ); S2 medioapically with a tong-like extension ( Fig. 21 ); S4 shortened, largely hidden by S3; S5 with two transverse rows of spines at basal margin, number 7 at left side and 6 at right side, and the spines nearly equidistant and of equal length ( Fig. 21 ); apical margin of S5 with setae and distinctly concave ( Fig. 21 ); hind trochanter ventrally normal, without angular projection, hind femur weakly swollen, apical lobe of hind tibia blunt and large ( Fig. 22 ); genitalia robust ( Figs 24–25 ), gonobase twice wider than long, gonocoxite wide and polished, laterally no much deviating from gonobasal outline ( Fig. 25 ), dorsal gonostylus massive elongate round-shape, upper apical margin with sparse and fine setae ( Fig. 25 ), ventral gonostylus forming a retrorse massive round-shape lobe, arising from center of gonocoxite, and flexed medially, apically irregularly truncate, centrally and peripherally glabrous ( Fig. 25 ); S7 ( Fig. 26 ) with median part triangular, apically forming a slender and glabrous process; S8 ( Fig. 26 ) trapezoid, forming a massive median converse trapezoid process with a few long bristles apically, medioapical margin with two little processes. Head black, except clypeus yellowish-brown with blackish-brown mark laterally ( Figs 18–19 ); mesosoma black ( Fig. 17 ), except pronotal lobe yellowish-brown; T1–2 pale yellowish-brown with blackish-brow band ( Fig. 20 ); S1–3 pale yellowish-brown, S5 blackish-brown, S6 black ( Fig. 21 ); legs yellowish-brown, except coxae, out-surface of fore trochanteres and basal out-surface of fore femur ( Figs 17, 20, 22 ). Vertex, low part of frontal area, malar area and genal area covered with short yellowish-white plumose pilosity ( Figs 18–19 ); parts of mesosoma also covered with pale yellowish-white plumose hairs in different length.

Female. BL=10.5–13.0 mm ( Fig. 27 ). Head obviously longer than broad, HL: HW=65: 56 ( Fig. 28 ); antenna geniculate ( Fig. 28 ), flagellum 10-segmented; malar area slightly longer than the width of mandible base (12:10), and about one-third as long as eye length (12:38) ( Fig. 29 ); gena as broad as eye, GW: EW=14: 14 ( Fig. 29 ); second submarginal crossvein straight, not angulated medially and reaching the radical nervure ( Fig. 30 ); T1 polished, disc with microscopically very sparse and fine punctures, two round spots ( Fig. 31 ); hind tibial spur coarsely serrate with the first teeth well-developed ( Fig. 32 ). Clypeus, low part of paraocular lobe rust yellow ( Fig. 28 ); supraclypeal area black ( Fig. 28 ); basal part of mandible rust yellow, apical part reddish-black ( Figs 28–29 ); scape reddish-brown ( Fig. 28 ); terga black, except T1 yellowish-brown, and T2–4 without broad orange apical margin ( Fig. 31 ); fore leg yellowish-brown ( Fig. 28 ), hind leg blackish ( Fig. 32 ). Vertex, low part of frontal area, malar area and genal area covered with short yellowish-white plumose pilosity ( Figs 28–29 ); sloping anterior surface of T1 covered with erect golden simple hairs ( Fig. 31 ); T1–4 with yellowish-white laterally directed simple hairs on tergal apical marginal zones; hind femur covered with long golden plumose hairs ( Fig. 31 ).

Material examined. Holotype. ♂, China, Yunnan, Xishuangbanna, NWNR: Anma Xinzai (100º39′E, 22º12′N), 13.VI.2013, coll. Pia Oremek. Paratypes. China, Yunnan, Xishuangbanna, NWNR: Mandian (100º40′E, 22º07′N), 1♀, 746 m, 8.VII.2008, coll. A. Weigel; Manfei (100º40′E, 22º08′N), 1♀, 26.VII.2013, coll. Pia Oremek; Naban (100º40′E, 22º09′N), 2♀, 709 m, 26.IV.2009, coll. Lingzeng Meng.

Distribution. China (Yunnan).

Etymology. The type location Yunnan is used to name the species.

Figures

Figures 17 – 22. Thrinchostoma (T.) yunnanense Niu & Zhu, sp. nov., male. 17. Habitus, lateral view. 18. Head, frontal view. 19. Head, lateral view. 20. Metasoma, dorsal view, showing T 1 – 2. 21. Metasoma, ventral view. 22. Hind leg, lateral view, showing the trochanter, femur and tibia. Scale bars = 1 mm.

Figures 23 – 26. Thrinchostoma (T.) yunnanense Niu & Zhu, sp. nov., male. 23. Fore wing, dorsal view, showing second submarginal crossvein and the hair spot. 24. Genitalia, dorsal view. 25. Genitalia, lateral view. 26. S 7 – 8, ventral view. Scale bars = 1 mm.

Figures 27 – 32. Thrinchostoma (T.) yunnanense Niu & Zhu, sp. nov., female. 27. Habitus, lateral view. 28. Head, frontal view. 29. Head, lateral view. 30. Fore wing, dorsal view, showing second submarginal crossvein stright medially. 31 Metasoma, dorsal view, showing T 1 – 2. 32. Hind tibia, showing the inner tibial spur. Scale bars = 1 mm.